Four Engineering Breakthroughs Changing the Skyscraper Race

As the world's tallest buildings reach toward the 3000 ft. mark and beyond, the pursuit of height might give way to practicality. From Dubai to Taipei and Chicago to Boston, the engineers of budding superstructures get plenty of attention for the tale of the tape. But as some of the field's leaders tell PM, they are also beginning to install new technology that will increase safety in skyscrapers currently on the rise.

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It's not all about civic virtue, either. "In order to be economical in designing buildings at these extreme heights, you have to look at the constructability, controlling the wind forces and the structural efficiency," says William Baker, the lead engineer for the Burj Dubai tower (pictured above) at Skidmore, Owings & Merrill LLP.

Those demands have already translated into new construction designs and next-gen materials that, however unheralded, will help keep future megatowers safe during construction, everyday use and disaster.

Steel has remained the veritable backbone of the building industry since it became easier to produce the alloy in the 17th century. But the heating process that allows engineers to create steel can also be its undoing: Above 750 F, steel starts to lose its structural integrity, and at 1100 F, steel loses 50 percent of its strength.

The current method for increasing steel's resistance to heat is a spray-on material, but that requires careful maintenance and increased costs. Adding certain metals, such as copper, has also shown to increase strength in high temperatures. Gregory Olson, a materials science engineer at Northwestern University, has been working with the Navy to develop high-performance steel that is both strong and heat resistant. Olson's formula infuses steel with nanoscale copper particles, this formula could maintain structural integrity at temperatures up to 1000 degrees F.

The formula for concrete has been continually improved since the Romans created a mixture of slaked lime and volcanic ash nearly 2500 years ago. But modern engineering provides plenty of room for improvement as researchers take advantage of new materials.

Among the newest developments: concrete reinforced with whisker-thin steel fibers and carbon nanotubes to increase strength. Those nanotubes, tested by MIT professor John E. Fernandez, give the concrete flexibility to prevent cracking, and when cracks do occur the nanotubes can bridge the divide and stop them from spreading. If those tiny tubes could be filled with a bonding agent, the concrete could also heal itself.

Like your yoga teacher, building designers are looking inward to the core of a building for additional strength.

New York's Freedom Tower, perhaps the most scrutinized building in terms of safety features, will be built around a 3 ft. reinforced concrete core wall that will help transfer loads throughout the building. "This tower was designed to be redundant," lead designer Jeffrey Holmes says. "If something happens to a column or a beam, there's plenty of strength and robustness so the building can heal itself by transferring loads to other areas."

The tower's safety systems--elevators, electrical risers, communications antennas, stairs and sprinklers--will exceed New York City building code requirements.

The Freedom Tower has extra-wide exit stairways, an extensive sprinkler and chemical filtration system, and emergency access within the core of the structure, which includes an extra stairway for emergency responders. Burj Dubai, meanwhile, has expanded its evacuation procedures with a "lifeboat" elevator mode that includes 10 high-speed shuttles, among them two fire service cars in the concrete core.

As those towers go up, researchers continue to suggest more unconventional systems. An Israeli company called Escape Rescue Systems suggests that building managers have collapsible escape cabins stored on the roof. The cabins, which could carry 150 people, would swing onto the side of the building and descend to the ground quickly.